function showThisDiv(liDiv) {
	var imageDiv = document.getElementById("hostory_book_list")
			.getElementsByTagName("div");
	for ( var i = 0; i < imageDiv.length; i++) {
		imageDiv[i].style.display = "none";
	}
	for ( var j = 0; j < liDiv.childNodes.length; j++) {
		if (liDiv.childNodes[j].nodeName == "DIV") {
			liDiv.childNodes[j].style.display = "block";
		}
	}
}